ELEASE NOTES

FIX BUGS:
[TD-1407]: fix an issue coverity reports getenv() return a strin…
[TD-1423]: fix bugs in group by nchar/binary columns.
[TD-1391]: fix bugs in release obj in submit processing.
[TD-1459]: fix compile error for release build type.
[TD-225]: fix compiler error in win platform
[TD-1245]: fix compile error
[TD-1478]: update sim script.

TEST:
[TD-1389]: Update null value test
[TD-1410]: add a tool for test JDBC Connector
[TD-1329]: add test case for incorrect count query
[TD-1478]: add test case query groupby with interval
[TD-804]: add test case for metadata update